wip: implement transportation, pickups and parking

src/Form/Model/ParticipantDto.php

@@ -60,8 +60,8 @@ class ParticipantDto
     public ?Pickup $pickupOutbound = null;
     public ?Pickup $pickupInbound = null;
 
-    // Parking service for self-organized transportation
-    public ?Service $parking = null;
+    // Parking service for self-organized transportation (boolean: true if parking requested)
+    public bool $parking = false;
 
     // Deprecated properties for backward compatibility - will be removed in future version
     public ?Service $transportationServiceTo = null;